Question

Afla numerele a,b, c, stiind ca a+b=300 , b+c=500, iar a+c=400

Answer 1

a+b=300   300-a=b  300-b=a  300-100=b  300-200=a  300-100=200  300-200=100
a+c=400   400-a=c  400-c=a  400-100=c  400-300=a  400-100=300  400-300=100
a=100
a+b=300   300-a=b  300-b=a  300-100=b  300-200=a  300-100=200  300-200=100
b+c=500   500-b=c  500-c=b  500-200=c  500-300=b  500-200=300  500-300=200
b=200
b+c=500   500-b=c  500-c=b  500-200=c  500-300=b  500-200=300  500-300=200
a+c=400   400-a=c  400-c=a  400-100=c  400-300=a  400-100=300  400-300=100
c=300

Answer 2

A+B+C=
-------------------,--------
A+B=300
B+C=500
A+C=400
-------------------,
A+B=?
500-300=200 (A)
500-200=300 (B)
----------------------------
B+C=?
300+C=500
C=500-300
C=200
----------------------
A+C=?
200+C=400
C=400-200
C=200
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